Biomass derived diketones as efficient visible light photoinitiators

ABSTRACT

Isatin derivatives, and methods of using isatin and isatin derivatives as photoinitiators, are described.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.63/026,237 filed under 35 U.S.C. § 111(b) on May 18, 2020, thedisclosure of which is incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with no government support. The government hasno rights in this invention.

BACKGROUND

Tunable photoinitiators are of wide spread need for a wide array ofapplications in photopolymerization reactions ranging from generatingcontact lenses, automobile parts, 3D printing, resin curing, silicones,epoxies, dental composites, aircraft parts, and composites. However,conventional photoinitiators are not very efficient, relying onforbidden transitions, which takes a significant amount of initiator.Furthermore, most conventional photoinitiators require UV light. Thereis a need in the art for new and improved photoinitiators.

SUMMARY

Provided is a composition comprising compound of Formula I:

wherein dashed lines indicate optional bonds; A is aryl, heterocyclic,carbocyclic, alkenyl, alkenyl, alkynyl, or alkyl; and X is O, S, NH, Ge,NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C), where R^(C) is alkyl, aryl,or heteroaryl; provided, however, that the compound is not isatin. Alsoprovided are salts, stereoisomers, racemates, solvates, hydrates, andpolymorphs thereof. The dashline component can also be derived frombiomass.

Further provided herein is a composition comprising a compound ofFormula II:

wherein dashed lines indicate optional bonds; A is aryl, heterocyclic,carbocyclic, alkenyl, alkenyl, alkynyl, or alkyl; X is O, S, NH, Ge,NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C), wherein R^(C) is alkyl, aryl,or heteroaryl; and Z is N, O, or S; provided, however, that the compoundis not isatin. Also provided are salts, stereoisomers, racemates,solvates, hydrates, and polymorphs thereof. The dashline component canalso be derived from biomass.

Further provided is a composition comprising a compound of Formula III:

wherein X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),wherein R^(C) is alkyl, aryl, or heteroaryl; and substituents R², R³,R⁴, and Y can be any combination of H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes; provided, however, that the compound is not isatin. Alsoprovided are salts, stereoisomers, racemates, solvates, hydrates, andpolymorphs thereof.

Further provided is a composition comprising formula A:

where dashed lines represent a linker that can be an alkyl chain, acarbocycle, a heterocyclic moiety, or a combination of C—C orC-heteroatom bonds, optionally substituted with one or more halogens,that links X to Y; Y is C═O, C═S, NR¹, PR², PR¹R², S, or Se; X is C═O,C═S, NR¹, P(R²)₂, PR¹R², S, or Se; Z is O, S, or Se; each R¹ is,independently, H, alkyl, aryl, aryloxy, alkoxy, or halo-substitutedalkoxy, and each R² is, independently, H, O, alkyl, aryl, aryloxy,alkoxy, N-alkyl, halo-substituted alkoxy, or halo-substituted N-alkyl;provided, however, that at least one of X or Y is C═O; further providedthat when the linker is phenyl, neither Y nor X is NH.

In certain embodiments, Y and Z have a cis orientation. In certainembodiments, Y is C═O. In certain embodiments, Z is O. In certainembodiments, X is NR¹. In certain embodiments, Y is C═O and X is NR¹. Incertain embodiments, X is NR¹; and R¹ is selected from the groupconsisting of alkyl, aryl, methoxy, phenoxy, and fluoro-substitutedmethoxy. In certain embodiments, Y is C═O; X is NR¹; and R¹ is selectedfrom the group consisting of alkyl, aryl, methoxy, phenoxy, andfluoro-substituted methoxy. In certain embodiments, the linker is anaryl group.

In certain embodiments, the composition has formula B:

In certain embodiments, the composition comprises N-methyl isatin 3c:

In certain embodiments, the composition comprises N-aryl isatin 3d:

In certain embodiments, the composition comprises N-acetyl isatin 3e:

In certain embodiments, the composition comprises N-benzoyl isatin 3f:

In certain embodiments, the composition comprises N-trifluoromethylisatin 3g:

Further provided is a composition comprising a compound of Formula IP-1:

wherein X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),wherein R^(C) is alkyl, aryl, or heteroaryl; substituents R², R³, R⁴,and Y can be any combination of H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes; and the polymer unit is vinyl, stryl, acryl, or a cyclicmonomer selected from lactones (cyclic esters), epoxides, lactides,lactams, silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the compound is compound IP-1a:

In certain embodiments, the compound is compound IP-1c:

In certain embodiments, the compound is compound IP-1d:

In certain embodiments, the compound is compound IP-1e:

In certain embodiments, the compound is a compound of Formula IP-1b:

wherein R^(M) is alkyl, aryl, heteroaryl, alkoxy, carboxy alkyl, or anamide.

In certain embodiments, the compound is compound IP-1f:

wherein n is an integer.

In certain embodiments, the compound is compound IP-1g:

wherein n is an integer.

In certain embodiments, the compound is compound IP-1h:

wherein n is an integer.

In certain embodiments, the compound is compound IP-1i:

wherein n is an integer.

Further provided is a composition comprising a compound of Formula IP-2:

wherein X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),wherein R^(C) is alkyl, aryl, or heteroaryl; the amine unit is an amine,thiol, or any hydrogen atom donor; and the vinyl, stryl, acryl, or acyclic monomer selected from lactones (cyclic esters), epoxides,lactides, lactams, silicon-containing cyclic monomers, and cycliccarbonates.

In certain embodiments, the compound is compound IP-2a:

In certain embodiments, the compound is compound IP-2b:

In certain embodiments, the compound is compound IP-2c:

In certain embodiments, the compound is compound IP-2d:

In certain embodiments, the compound is compound IP-2e:

In certain embodiments, the compound is compound IP-2f:

wherein m and n are each integers.

In certain embodiments, the compound is compound IP-2g:

wherein n is an integer.

Further provided is a composition comprising a compound of Formula IP-3:

wherein the amine unit can be an amine, thiol, or any hydrogen atomdonor.

In certain embodiments, the compound is compound IP-3a:

In certain embodiments, the compound is compound IP-3b:

Further provided is a composition comprising a compound of Formula IP-4:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and Y is selected from H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes.

In certain embodiments, the compound is compound IP-4a:

In certain embodiments, the compound is compound IP-4b:

Further provided is a composition comprising a compound of Formula IP-5:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and Y is selected from H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes.

In certain embodiments, the compound is compound IP-5a:

In certain embodiments, the compound is compound IP-5b:

In certain embodiments, the compound is compound IP-5c:

Further provided is a composition comprising a compound of Formula IP-6:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the vinyl, stryl, acryl, or a cyclic monomer selected fromlactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the compound is compound IP-6a:

In certain embodiments, the compound is compound IP-6b:

Further provided is a composition comprising a compound of Formula IP-7:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy.

In certain embodiments, the compound is compound IP-7a:

In certain embodiments, the compound is compound IP-7b:

In certain embodiments, the compound is compound IP-7c:

In certain embodiments, the compound is compound IP-7d:

In certain embodiments, the compound is compound IP-7e:

Further provided is a composition comprising a compound of Formula IP-8:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy.

In certain embodiments, the compound is compound IP-8a:

In certain embodiments, the compound is compound IP-8b:

Further provided is a composition comprising a compound of Formula IP-9:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the vinyl, stryl, acryl, or a cyclic monomer selected fromlactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the compound is compound IP-9a:

In certain embodiments, the compound is compound IP-9b:

Further provided is a composition comprising a compound of FormulaIP-10:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the vinyl, stryl, acryl, or a cyclic monomer selected fromlactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the compound is compound IP-10a:

In certain embodiments, the compound is compound IP-10b:

Further provided is a method for making a polymer, the method comprisingexposing a photoinitiator and a monomer to light to produce a polymer,wherein the photoinitiator is isatin or an isatin derivative. In certainembodiments, the photoinitiator is isatin. In certain embodiments, thepolymer is colorless or transparent.

In certain embodiments, the photoinitiator has Formula I:

wherein dashed lines indicate optional bonds; A is aryl, heterocyclic,carbocyclic, alkenyl, alkenyl, alkynyl, or alkyl; and X is O, S, NH, Ge,NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C), where R^(C) is alkyl, aryl,or heteroaryl.

In certain embodiments, the photoinitiator has Formula II:

wherein dashed lines indicate optional bonds; A is aryl, heterocyclic,carbocyclic, alkenyl, alkenyl, alkynyl, or alkyl; X is O, S, NH, Ge,NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C), wherein R^(C) is alkyl, aryl,or heteroaryl; and Z is N, O, or S.

In certain embodiments, the photoinitiator has Formula III:

wherein X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),wherein R^(C) is alkyl, aryl, or heteroaryl; and substituents IV, R²,R³, R⁴, and Y can be any combination of H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes.

In certain embodiments, the photoinitiator has Formula A:

where dashed lines represent a linker that can be an alkyl chain, acarbocycle, a heterocyclic moiety, or a combination of C—C orC-heteroatom bonds, optionally substituted with one or more halogens,that links X to Y; Y is C═O, C═S, NR¹, P(R²)₂, PR¹R², S, or Se; X isC═O, C═S, NR¹, P(R²)₂, PR¹R², S, or Se; Z is O, S, or Se; each R¹ is,independently, H, alkyl, aryl, aryloxy, alkoxy, or halo-substitutedalkoxy, and each R² is, independently, H, O, alkyl, aryl, aryloxy,alkoxy, N-alkyl, halo-substituted alkoxy, or halo-substituted N-alkyl;provided, however, that at least one of X or Y is C═O, and X and Z havea cis orientation. In particular embodiments, Y is C═O. In particularembodiments, Z is O. In particular embodiments, X is NR¹. In particularembodiments, Y is C═O and X is NR¹. In particular embodiments, X is NR¹;and R¹ is selected from the group consisting of alkyl, aryl, methoxy,phenoxy, and fluoro-substituted methoxy. In particular embodiments, Y isC═O; X is NR¹; and R¹ is selected from the group consisting of alkyl,aryl, methoxy, phenoxy, and fluoro-substituted methoxy. In particularembodiments, the linker is an aryl group.

In particular embodiments, the photoinitiator has formula B:

In certain embodiments, the photoinitiator comprises isatin 3a:

In certain embodiments, the photoinitiator comprises N-methyl isatin 3c:

In certain embodiments, the photoinitiator comprises N-aryl isatin 3d:

In certain embodiments, the photoinitiator comprises N-acetyl isatin 3e:

In certain embodiments, the photoinitiator comprises N-benzoyl isatin3f:

In certain embodiments, the photoinitiator comprises N-trifluoromethylisatin 3g:

In certain embodiments, the photoinitiator is prepared from biomass. Incertain embodiments, the light is visible light. In certain embodiments,the light is purple light. In certain embodiments, the light is bluelight. In certain embodiments, the light is green light.

In certain embodiments, the monomer is methylmethacrylate 4:

In particular embodiments, the polymer is polymer 5:

where n is an integer.

In certain embodiments, the monomer is furfuryl dimethacrylate monomer6:

In certain embodiments, the monomer is dimethylmethacrylate monomer 8:

In certain embodiments, the photoinitiator is a compound of FormulaIP-1:

wherein X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),wherein R^(C) is alkyl, aryl, or heteroaryl; substituents R², R³, R⁴,and Y can be any combination of H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes; and the vinyl, stryl, acryl, or a cyclic monomer selectedfrom lactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the photoinitiator is compound IP-1a:

In certain embodiments, the photoinitiator is compound IP-1c:

In certain embodiments, the photoinitiator is compound IP-1d:

In certain embodiments, the photoinitiator is compound IP-1e:

In certain embodiments, the photoinitiator is a compound of FormulaIP-1b:

wherein R^(M) is alkyl, aryl, heteroaryl, alkoxy, carboxy alkyl, or anamide.

In certain embodiments, the photoinitiator is compound IP-1f:

wherein n is an integer.

In certain embodiments, the photoinitiator is compound IP-1g:

wherein n is an integer.

In certain embodiments, wherein the photoinitiator is compound IP-1h:

wherein n is an integer.

In certain embodiments, the photoinitiator is compound IP-1i:

wherein n is an integer.

In certain embodiments, the photoinitiator is a compound of FormulaIP-2:

wherein X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),wherein R^(C) is alkyl, aryl, or heteroaryl; the amine unit is an amine,thiol, or any hydrogen atom donor; and the vinyl, stryl, acryl, or acyclic monomer selected from lactones (cyclic esters), epoxides,lactides, lactams, silicon-containing cyclic monomers, and cycliccarbonates.

In certain embodiments, the photoinitiator is compound IP-2a:

In certain embodiments, the photoinitiator is compound IP-2b:

In certain embodiments, the photoinitiator is compound IP-2c:

In certain embodiments, the photoinitiator is compound IP-2d:

In certain embodiments, the photoinitiator is compound IP-2e:

In certain embodiments, the photoinitiator is compound IP-2f:

wherein m and n are each integers.

In certain embodiments, the photoinitiator is compound IP-2g:

wherein n is an integer.

In certain embodiments, the photoinitiator is a compound of FormulaIP-3:

wherein the amine unit can be an amine, thiol, or any hydrogen atomdonor.

In certain embodiments, the photoinitiator is compound IP-3a:

In certain embodiments, the photoinitiator is compound IP-3b:

In certain embodiments, the photoinitiator is a compound of FormulaIP-4:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and Y is selected from H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes.

In certain embodiments, the photoinitiator is compound IP-4a:

In certain embodiments, the photoinitiator is compound IP-4b:

In certain embodiments, the photoinitiator is a compound of FormulaIP-5:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and Y is selected from H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes.

In certain embodiments, the photoinitiator is compound IP-5a:

In certain embodiments, the photoinitiator is compound IP-5b:

In certain embodiments, the photoinitiator is compound IP-5c:

In certain embodiments, the photoinitiator is a compound of FormulaIP-6:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the polymer unit is vinyl, stryl, acryl, or a cyclicmonomer selected from lactones (cyclic esters), epoxides, lactides,lactams, silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the photoinitiator is compound IP-6a:

In certain embodiments, the photoinitiator is compound IP-6b:

In certain embodiments, the photoinitiator is a compound of FormulaIP-7:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy.

In certain embodiments, the photoinitiator is compound IP-7a:

In certain embodiments, the photoinitiator is compound IP-7b:

In certain embodiments, the photoinitiator is compound IP-7c:

In certain embodiments, the photoinitiator is compound IP-7d:

In certain embodiments, the photoinitiator is compound IP-7e:

In certain embodiments, the photoinitiator is a compound of FormulaIP-8:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy.

In certain embodiments, the photoinitiator is compound IP-8a:

In certain embodiments, the photoinitiator is compound IP-8b:

In certain embodiments, the photoinitiator is a compound of FormulaIP-9:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the polymer unit is vinyl, stryl, acryl, or a cyclicmonomer selected from lactones (cyclic esters), epoxides, lactides,lactams, silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the photoinitiator is compound IP-9a:

In certain embodiments, the photoinitiator is compound IP-9b:

In certain embodiments, wherein the photoinitiator is a compound ofFormula IP-10:

wherein R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and polymer unit is vinyl, stryl, acryl, or a cyclic monomerselected from lactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, and cyclic carbonates.

In certain embodiments, the photoinitiator is compound IP-10a:

In certain embodiments, the photoinitiator is compound IP-10b:

In certain embodiments, a co-initiator is exposed to the light with thephotoinitiator and the monomer. In particular embodiments, theco-initiator comprises O-xylene, triethanol amine,1,4-diazabicyclo[2.2.2]octane, or phenol.

In certain embodiments, the photoinitiator and the monomer are in asolvent. In particular embodiments, the solvent comprises o-xylene,MeCN, toluene, or a combination thereof.

In certain embodiments, the light is a 50 mW light.

In certain embodiments, the polymer is used to make a dental composite,to prepare a bone substitute material, or for bio-reconstruction.

Further provided is a kit for making a polymer, the kit comprising afirst container housing a monomer, and a second container housing isatinor an isatin derivative.

Further provided is a photoinitiator comprising an isatin derivativecapable of initiating a polymerization of a monomer into a transparentpolymer upon exposure to visible light.

Further provided is the use of isatin or an isatin derivative as aphotoinitiator. Further provided is the use of isatin or an isatinderivative as a photoinitiator for manufacturing parts fortransportation, composites, electronics, or construction.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file may contain one or more drawings executedin color and/or one or more photographs. Copies of this patent or patentapplication publication with color drawing(s) and/or photograph(s) willbe provided by the U.S. Patent and Trademark Office upon request andpayment of the necessary fees.

FIG. 1 : α-Diketone derivatives—skeletons with photoinitiator abilities.The colors of the isatin derivatives 3a-3g are shown below eachstructure.

FIG. 2 : Scheme 1, showing isatin photoinitiators. Inset: absorptionspectra of isatin derivatives 3a-3f with optical density in parenthesis.

FIG. 3 : Photographs showing the photopolymerization ofmethylmethacrylate 4 with various isatin derivatives using a blue LED.

FIG. 4 : Scheme 2, showing isatin derivative 3e-mediatedphotopolymerization of 6 and 8.

FIG. 5 : Chemical structures of isatin 3a, isatin derivatives 3b-3g,monomers 4, 6, 8, and corresponding polymer products 5, 7, 9.

FIG. 6 : Scheme 3, depicting the non-limiting example synthesis ofN-methyl isatin 3c.

FIGS. 7A-7B: ¹H NMR spectrum (FIG. 7A) and ¹³C NMR spectrum (FIG. 7B) ofN-methyl isatin 3c.

FIG. 8 : Scheme 4, depicting the non-limiting example synthesis ofN-acetyl isatin derivative 3e.

FIGS. 9A-9B: ¹H NMR spectrum (FIG. 9A) and ¹³C NMR spectrum (FIG. 9B) ofN-acetyl isatin derivative 3e.

FIG. 10 : Scheme 5, depicting the non-limiting example synthesis ofN-benzoyl isatin derivative 3f.

FIGS. 11A-11B: ¹H NMR spectrum (FIG. 11A) and ¹³C NMR spectrum (FIG.11B) of N-benzoyl isatin derivative 3f.

FIG. 12 : Scheme 6, depicting the non-limiting example synthesis of2,5-bis(hydroxymethyl) furan 15.

FIGS. 13A-13B: ¹H NMR spectrum (FIG. 13A) and ¹³C NMR spectrum (FIG.13B) of 2,5-bis(hydroxymethyl) furan 15.

FIG. 14 : Scheme 7, depicting the non-limiting example synthesis offurfuryl dimethacrylate monomer 6.

FIGS. 15A-15B: ¹H NMR spectrum (FIG. 15A) and ¹³C NMR spectrum (FIG.15B) of furfuryl dimethacrylate monomer 6.

FIG. 16 : U-Vis absorption spectra of isatin photoinitiators 3a-3f at aconcentration of 150 μM in MeCN.

FIG. 17 : Scheme 8, depicting the photopolymerization ofmethylmethacrylate 4 with isatin photoinitiators to produce polymer 5.

FIGS. 18A-18B: GPC traces for 5, when 10 was used assolvent/co-initiator (FIG. 18A), and when 11 was used as co-initiator inMeCN (FIG. 18B) and blue LED irradiation.

FIG. 19 : GPC traces for 5 when 11 is used as co-initiator in MeCN andpurple LED irradiation.

FIGS. 20A-20C: Laser flash photolysis: Triplet absorption spectra forisatins 3c (FIG. 20A), 3e (FIG. 20B), and 3f (FIG. 20C) in benzene underargon.

FIG. 21 : Top: Reaction mechanism for generating initiator radicals.Bottom: Determination of the bimolecular quenching rate constants k_(q)11 from the plot of the inverse triplet lifetimes of 3a, 3c, 3e, and 3fmeasured by laser flash photolysis and monitored at 420 nm (3a, 3c, 3f)and 450 nm (3e) vs. varying concentrations of 11 in benzene.

FIG. 22 : Top: Reaction mechanism for generating initiator radicals.Bottom left: Decay of the triplet absorbance of 3a after laserexcitation (308 nm, 15 ns pulse length) monitored at 420 nm indeoxygenated benzene (red) or o-xylene (blue). Bottom right:Determination of the bimolecular quenching rate constants k_(q) 10 fromthe plot of the inverse triplet lifetime of 3a measured by laser flashphotolysis vs. varying concentrations of o-xylene in benzene.

FIG. 23 : Top: Reaction mechanism for generating initiator radicals.Bottom: Decay of the triplet absorbance of 3e after laser excitation(308 nm, 15 ns pulse length) monitored at 450 nm in deoxygenated benzene(red) or o-xylene (blue). Triplet lifetime of 3e in o-xylene is 66 ns.

DETAILED DESCRIPTION

Throughout this disclosure, various publications, patents, and publishedpatent specifications are referenced by an identifying citation. Thedisclosures of these publications, patents, and published patentspecifications are hereby incorporated by reference into the presentdisclosure in their entirety to more fully describe the state of the artto which this invention pertains.

α-Diketone derivatives play a prominent role in many of the industrialand medical/dental processes that are initiated by light. One of thereasons the α-diketones are unique photochemical chromophores is theyposess low lying triplet states. A distinguishable feature of thesechromophores is that some of their derivatives (e.g., biacetylderivatives) display room temperature phosphorescence. An importantfeature that has a significant impact on the photophysicalcharacteristic of the α-diketone chromophore is the orientation of thecarbonyl group, i.e., s-cis and s-trans isomers of the dicarbonylsystem. The versatility of the α-diketone chromophore has enabled itsuse in polymer curing as well as in dental curing. In spite of its vastimpact in the field of material science, α-diketone derivatives that canbe fine-tuned in the visible region for initiation polymerizationreaction are currently very limited. The present disclosure describesthe development of α-diketone derivative chromophores and theutilization of these compounds as photoinitiators. The α-diketones-basedchromophores are amenable to visible light illumination and can beeasily accessed synthetically, even from bio-sources, in one or twosteps, with superior photochemical and photophysical properties.

Inspection of the α-diketone chromophores shown in FIG. 1 brings aboutthe realization that the s-cis orientation of the α-diketone isimportant for enhanced absorptivity in the visible region. As describedin the examples herein, isatin derivatives were analyzed, as they notonly feature an s-cis oriented α-carbonyl functionality, but also have astrong absorption in the visible region. Isatin has not previously beenshown to be a photoinitiator (either as a type I or type IIphotoinitiator). However, as shown herein, the enhanced absorptivity inthe visible light region by isatin and isatin derivatives, and theirexcepted low-lying triplet excited state, enable their use as visiblelight photoinitiators for conventional photoinitiated polymerization, 3Dprinting, dental curing, and a wide range of other applications.

Isatin belongs to the family of plant-derived compounds calledtribulins, featuring an indole core that was first isolated in 1840 byOtto Linné Erdman and Auguste Laurent by oxidation of indigo dyes. As anatural product with bright orange color, isatin is found in manynatural products (e.g., in Brazil nut trees). In spite of featuringbright colors, the photochemistry and photophysical features of isatinhave not been well explored. In accordance with the present disclosure,due to the presence of dicarbonyl functionality, isatin and isatinderivatives can be tailored to be highly efficient photoinitiators (PI)with excellent absorptivity in the visible region (FIG. 3 ). Todemonstrate this, a family of isatin derivates 3a-3g was synthesized (ina single step) and evaluated as photoinitiators (FIG. 1 ). Based onphotophysical studies, it is revealed in the examples herein thatisatins can be employed as highly efficient photoinitiators at workunder visible light illumination.

In general, the isatin derivatives described herein may have thefollowing Formula I:

where dashed lines indicate optional bonds; A is aryl, heterocyclic,carbocyclic, alkenyl, alkenyl, alkynyl, or alkyl; and X is O, S, NH, Ge,NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C), where R^(C) is alkyl, aryl,or heteroaryl.

The isatin derivatives may have the following Formula II:

where dashed lines indicate optional bonds; A is aryl, heterocyclic,carbocyclic, alkenyl, alkenyl, alkynyl, or alkyl; X is O, S, NH, Ge,NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C), where R^(C) is alkyl, aryl,or heteroaryl; and Z is N, O, or S.

The isatin derivatives may have the following Formula III:

where X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),where R^(C) is alkyl, aryl, or heteroaryl; and substituents IV, R², R³,R⁴, and Y can be any combination of H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes.

As shown in the examples herein, the isatin derivatives may includecompounds having Formula A:

where dashed lines represent a linker that can be an alkyl chain, acarbocycle, a heterocyclic moiety, or a combination of C—C orC-heteroatom bonds, optionally substituted with one or more halogens,that links X to Y; Y is C═O, C═S, NR¹, P(R²)₂, PR¹R², S, or Se; X isC═O, C═S, NR¹, P(R²)₂, PR¹R², S, or Se; Z is O, S, or Se; each R¹ is,independently, H, alkyl, aryl, aryloxy, alkoxy, or halo-substitutedalkoxy, and each R² is, independently, H, O, alkyl, aryl, aryloxy,alkoxy, N-alkyl, halo-substituted alkoxy, or halo-substituted N-alkyl;provided that at least one of X or Y is C═O. For efficient use asphotoinitiators, X and Z should have a cis orientation. Cis carbonylsabsorb in the visible range, whereas trans carbonyls do not absorb inthe visible range. In some embodiments, the isatin derivatives haveformula B:

where R¹ is the same R¹ as described above, namely, H, alkyl, aryl,aryloxy, alkoxy, or halo-substituted alkoxy. In particular embodiments,R¹ is selected from the group consisting of alkyl, aryl, methoxy,phenoxy, and fluoro-substituted methoxy. Non-limiting example isatinderivatives include the isatin derivatives 3b-3g shown in FIG. 5 .

The isatin derivatives may also include isatins immobilized on polymersupports, such as in Formula IP-1:

where X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),where R^(C) is alkyl, aryl, or heteroaryl; substituents R², R³, R⁴, andY can be any combination of H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes; and polymer unit is vinyl, stryl, acryl, or cyclic monomerslike lactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, cyclic carbonates, or others.Non-limiting examples of such compounds include IP-1a, IP-1c, IP-1d,IP-1e, and compounds of Formula IP-1b:

where R^(M) is alkyl, aryl, heteroaryl, alkoxy, carboxy alkyl, or anamide. Additional examples include the compounds IP-1f, IP-1g, IP-1h,and IP-1i:

where n is an integer.

The isatin derivatives may also include isatins having amine unitsimmobilized on polymer supports, such as in Formula IP-2:

where X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),where R^(C) is alkyl, aryl, or heteroaryl; the amine unit can be anamine, thiol, or any hydrogen atom donor; and the polymer unit is vinyl,stryl, acryl, or cyclic monomers like lactones (cyclic esters),epoxides, lactides, lactams, silicon-containing cyclic monomers, cycliccarbonates, or others. Non-limiting examples of such compounds includecompounds IP-2a, IP-2b, IP-2c, IP-2d, IP-2e, IP-2f, and IP-2g:

where m and n are each integers.

Furthermore, the isatin derivatives may also include isatins havingamine units but without polymer supports, such as compounds of FormulaIP-3:

wherein the amine unit can be an amine, thiol, or any hydrogen atomdonor. Non-limiting examples of such compounds are compounds IP-3a andIP-3b:

The isatin derivatives may include type I based isatin systems, such ascompounds having Formula IP-4:

where R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and Y is selected from H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes. Non-limiting examples of such compounds include compoundsIP-4a and IP-4b:

Type I isatin systems may further include compounds of Formula IP-5:

where R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and Y is selected from H, alkyl, alkene, alkynes, aryl,heterocyclic, alkenyl halides, unsaturated enones, unsaturated ketones,unsaturated amides, unsaturated alcohols, unsaturated amines,unsaturated thiols, phosphonates, carboxylates, sulfonates, nitriles,thioethers, thioamides, thioketones, azides, sulfides, disulfides,ethers, epoxides, nitrates, nitrites, nitro compounds, nitrosocompounds, alkyl ketoesters, acylgermanes, metallocenes, organosilanes,oximes, imides, cyanates, isocyanates, thiocyanates, isothiocyanates,sulfoxides, sulfones, sulfites, phosphites, thial, phosphines, andaldehydes. Non-limiting examples of such compounds include compoundsIP-5a, IP-5b, and IP-5c:

Type I isatin systems may further include polymer units, such ascompounds of Formula IP-6:

where R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the polymer unit is vinyl, stryl, acryl, or cyclic monomerslike lactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, cyclic carbonates, or others.Non-limiting examples of such compounds include compounds IP-6a andIP-6b:

Type I isatin systems may further include compounds of Formula IP-7:

where R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy. Non-limiting examples of such compounds include compoundsIP-7a, IP-7b, IP-7c, IP-7d, and IP-7e:

Type I isatin systems may further include compounds of Formula IP-8:

where R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy. Non-limiting examples of such compounds include compounds IP-8aand IP-8b:

Type I isatin systems may further include compounds bound to a polymersupport, such as compounds of Formula IP-9:

where R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the polymer unit is vinyl, stryl, acryl, or cyclic monomerslike lactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, cyclic carbonates, or others.Non-limiting examples of such compounds include compounds IP-9a andIP-9b:

Type I isatin systems may further include compounds of Formula IP-10:

where R^(C) is alkyl, alkenyl, aromatic, carbocyclic, heterocyclic, orcarboxy; and the polymer unit is vinyl, stryl, acryl, or cyclic monomerslike lactones (cyclic esters), epoxides, lactides, lactams,silicon-containing cyclic monomers, cyclic carbonates, or others.Non-limiting examples of such compounds include compounds IP-10a andIP-10b:

Advantageously, isatin and isatin derivatives are useful as efficientphotoinitiators for visible light-based polymerization. These initiatorscan be fine tuned for various wavelengths (purple, blue, green, etc.),and their unique excited state properties make them ideal candidates forreplacing well-established UVA light-based photoinitiators. The isatincompounds work with LED lights as the illumination source. Typical UVcuring uses a 1000 W light. In contrast, the isatin photoinitiatorsdescribed herein may be utilized with a 50 mW light, thereby providingenergy savings. The photoinitiation may work with wavelengths of lightall the way to green. The compounds are highly tunable to a specificwavelength depending on end application, and can be channeled forphotopolymerization reactions.

The isatin derivatives may also be plant-derived. Surprisingly, plantdye-based derivates have not previously been evaluated asphotoinitiators (either as type I or type II photoinitiators). Theirenhanced absorptivity in the visible light region and the exceptedlow-lying triplet excited state enables their use as visible lightphotoinitiators for conventional photoinitiated polymerization, 3Dprinting, and dental curing, for example. The need for such visiblelight initiators is of high demand as photoinitiators that use UV-curingare used in inks, imaging, dental composites, automobile partsmanufacturing, clear coatings in the printing industry, paints, andpackaging, to name a few. An added advantage is the generation oftransparent materials starting from colored photoinitiators. The isatinderivatives described herein can be used to create transparent orcolorless polymers, which further broadens their possible applications.The chromophore implementation is quite straight forward with enhancedefficiency, and low loading levels. This decreases coloration. Theresulting polymers may be transparent, and stable from yellowing. Thepolymers may be free from haze or fogging.

The photoinitiators described herein can be used in connection withelastomers, polymers, thermoplastics, composites, glues, resins, paints,pigments, contact lenses, automobile parts, 3D printing, resin curing,silicones, epoxies, dental composites (e.g., as an alternative tocamphorquinone 2), photo etching, aircraft parts, composites, and thelike. In some embodiments, the photoinitiators are used in biomendicalapplications such as for dental curing, bone hardening, or to makebandages. The photoinitiators can be used to initiate polymerization ofany monomer that can be photopolymerized. The final filament may becolorless or otherwise given no color from the photoinitiator. Thus, thephotoinitiators are useful to produce a wide range of plastics.

Furthermore, the photoinitiators described herein may be polymerized orotherwise incorporated into a polymer. For example, a polymer backbonemay include an isatin derivative dangling from it. Such polymercompositions are usable as type I or type II initiators.

The compositions and methods described herein can be embodied in theform of a kit or kits. A non-limiting example of such a kit is a kit forconducting a photopolymerization or making a polymer, the kit comprisinga monomer and isatin or an isatin derivative in separate containers,where the containers may or may not be present in a combinedconfiguration. Many other kits are possible, such as kits that furtherinclude a light source, such as an LED. The kits may further includeinstructions for using the components of the kit to practice the subjectmethods. The instructions for practicing the subject methods aregenerally recorded on a suitable recording medium. For example, theinstructions may be present in the kits as a package insert or in thelabeling of the container of the kit or components thereof. In otherembodiments, the instructions are present as an electronic storage datafile present on a suitable computer readable storage medium, such as aflash drive or CD-ROM. In other embodiments, the actual instructions arenot present in the kit, but means for obtaining the instructions from aremote source, such as via the internet, are provided. An example ofthis embodiment is a kit that includes a web address where theinstructions can be viewed and/or from which the instructions can bedownloaded. As with the instructions, this means for obtaining theinstructions is recorded on a suitable substrate.

Examples

In this example, isatin derivatives are compared to existing technologyand shown to have enhanced properties. Biomass derived diketones werefound to be efficient photoinitiators for visible light basedpolymerization. Their unique excited state properties make them idealcandidates for replacing well-established UVA light-based type 1 andtype 2 photoinitiators.

Isatin 3a and a family of isatin derivatives 3b-3g were synthesized, ina single step, and their use as photoinitators was evaluated (FIG. 1 ).Based on photophysical studies, it is revealed that these compounds areefficient photoinitiators that work under visible light illumination.

Commercially available isatin 3a can be conveniently functionalized tofeature alkyl (3c), aryl (3d), acyl (3e), benzoyl (3f), ortrifluoromethyl (3g) functionalities. Depending on the substitution onthe nitrogen, isatins display absorption in the visible region asillustrated by their bright colors (FIGS. 1, 3 ). To take advantage ofthis visible light absorptivity for initiating polymerization withvisible light, understanding the photophysical features becomes quiteimportant. As isatins feature a benzoyl carbonyl functionality, avisible light initiated hydrogen abstraction reaction that can bechannelled for polymerization reaction utilizing methylmethacrylate 4(Scheme 2, FIG. 4 ) is possible. An added advantage of this strategy isthat it enables polymerization reactions in which the solvent plays adual role as diluent and coinitiator (co-initiator 10, Scheme 1, FIG. 2), increasing the efficiency of the polymerization process.

The evaluation of the photopolymerization efficiency of isatin 3a andisatin derivatives 3b-3f began with o-xylene 10 and triethanolamine 11as co-initiators. Satisfactory conversions of monomer methylmethacrylate4 to polymer 5 was achieved (Table 1) under blue LED irradiation witho-xylene 10 as co-initiator/solvent. The reaction was also efficientwith triethanol amine 11 as the co-initiator in acetonitrile (6 hirradiation). Inspection of Table 1 shows that the % conversion in thecase of photoinitiators 3a-3d does not vary with the choice ofco-initiator. On other hand, N-acyl isatin derivatives 3e and 3f gaverelatively high polymer yield and the % conversions were around 17-19%.GPC analysis on the polymers showed polydispersities ranging from1.8-5.3, which is reasonable for a free radical polymerization process.Surprisingly, colored reaction mixtures 3e and 3f before irradiationturned colorless after reaction. Quenching the reaction samples withcold methanol resulted in polymer 5 as a white precipitate/gel. (FIG. 3.) Taking into consideration of absorptivity at wavelength ˜390 nm fromUV-Vis absorption studies, similar photopolymerization experiments wereperformed using purple LED irradiation. All the samples gave similar %conversion of monomer.

TABLE 1 Isatin photoinitiators for acrylate polymerization using blueLED irradiation Entry Isatin CI Monomer % Conversion^(c) Mn Mw PDI 1 3a10 4 6 46,916 98,450 2.0 2 3a 11 4 7 85,700 1,72,535 2.0 3 3b^(b) 10 4 —— — — 4 3b 11 4 11 73,554 2,20,504 2.0 5 3c 10 4 6 42,862 78,814 1.8 63c 11 4 7 1,07,294 2,15,521 2.1 7 3d 10 4 9 37,036 81,271 2.1 8 3d 11 47 1,08,092 2,48,628 2.3 9 3e 10 4 17 19,405 63,400 3.2 10 3e 11 4 983,228 4,48,088 5.3 11 3f 10 4 17 22,014 66,444 3.0 12 3f 11 4 71,128,22 2,67,774 2.3 ^(a)M = Monomer 4 = 3.12 M; isatin concentration =1.5 mM. CI = co-initiator 10 or 11. Concentration of co-initiator 11 wasused in equimolar concentrations to photoinitiator. o-Xylene 10 was usedboth as a solvent and a co-initiator when employed forphotopolymerization. For co-initiator 11, MeCN was employed as thesolvent. Photopolymerizations were performed with blue LED ~ 460 nm(strip taped on pyrex glass jar) illumination. Irradiation was done for3 h (for 10) and 6 h (for 11). 3^(b) is insoluble in o-xylene. ^(c)%conversion carry an error of 6% (average of three runs) and wascalculated gravimetrically = ratio of weight(g) of isolatedpolymer/weight(g) of the monomer used.

TABLE 2 Isatin photoinitiators for acrylate polymerization using purpleLED Isatin 3e Entry [2 mM] (1 equiv) 11 [mM] (equiv.) % Conversion^(b) 13e 0.2 mM (0.1 equiv) 2.6 2 3e 1.0 mM (0.5 equiv) 5.8 3 3e 2.0 mM (1.0equiv) 10.4 4 3e 4.0 mM (2.0 equiv) 8.6 5 3e 8.0 mM (4.0 equiv) 8.1 6 3e 10 mM (5.0 equiv) 7.5 aM = Monomer 4 = 3.12M; Isatin concentration =2.0 mM. Co-initiator = triethanol amine 11, solvent = MeCN. Blue LEDstrip illumination was employed for the photopolymerization with a fluxdensity of 1.27 mW/cm² (LED jar) and Ee = Flux density (mW/cm²) measuredby Thor PM100D power meter console using S121C photodiode power sensorby keeping the sample at a distance of ~3 cm from the light source.Irradiation was done for 6 h. ^(b) % conversion carry an error of 5% andwas calculated gravimetrically = ratio of weight(g) of isolatedpolymer/weight(g) of the monomer used. The values reported are anaverage of three run.

TABLE 3 Isatin photoinitiators for acrylate polymerization using purpleLED Entry Isatin CI Monomer % Conversion^(b) Mn Mw PDI 1 3a 11 4 786,105 1,56,606 1.8 2 3b 11 4 <1 86,337 1,65,490 1.9 3 3c 11 4 91,01,115 2,19,813 2.1 4 3d 11 4 10 85,626 1,81,794 2.1 5 3e 11 4 878,526 2,57,136 3.2 6 3f 11 4 8 1,28,547 2,52,197 1.9 ^(a)M = Monomer 4= 3.12 M; isatin concentration = 1.5 mM. Concentration of co-initiator11 was used in equimolar concentrations to photoinitiator.Photopolymerizations were performed in MeCN with purple LED ~ 390 nm(strip taped on pyrex glass jar) illumination. Irradiation was done for6 h. ^(b)% conversion carry an error of 7% (average of three runs) andwas calculated gravimetrically = ratio of weight(g) of isolatedpolymer/weight(g) of the monomer used. The values reported are anaverage of three runs.

In order to demonstrate the usability of the visible light activephotoinitiators for industrial applications, a biomass-derived furfuraldimethacrylate derivative was used as the monomer to make cross-linkedpolymers. A 50-50% blend of monomer 6 or 8 and 3e in o-xylene was placedin a silicone mold. The samples were irradiated by blue LED for 3 h.After the photoreaction, the solvent was removed by placing thecross-linked polymer product in vacuum dry oven for ˜12 h. The formationof a transparent thin film without any coloration from isatin 3e wasobserved after curing (Scheme 2, FIG. 2 ). Without wishing to be boundby theory, it is believed that the isatin functionality is incorporatedwithin the polymer backbone in which the benzoyl carbonyl group isreduced, leading to a transparent film. 3g was synthesized to test itsefficiency as a photoinitiator based on polymerization results onN-acetyl 3e and N-benzoyl 3f derivatives from Table 1.

To understand the excited state processes involved leading to radicalgeneration and their kinetics, photophysical studies were performed onisatin derived photoinitiators 3a, 3c, 3e, and 3f. To investigate thetriplet state properties at room temperature, transient absorptionmeasurements were performed using a pulsed laser for excitation ofλ_(ex)=308 nm for 3e and λ_(ex)=355 nm for 3c and 3f. FIGS. 20A-20C showthe transient absorption spectra of 3c, 3e, and 3f, which were assignedto triplet-triplet absorptions. The spectra of 3a was consistent withliterature reports. The triplet states decayed with lifetimes between of9 is for 3a, 7.1 is for 3c (Table 4). Placing the electron withdrawingacyl substituent on the isatin nitrogen lowered lifetimes to 0.066 isand 0.48 is for 3e and 3f, respectively.

TABLE 4 Photophysical kinetic parameters for various isatins 3a 3c 3e 3fτT (ps) in benzene 9.0 7.1 0.066 0.48 k_(q) ¹¹ (10⁸ M⁻¹ s⁻¹) 2.8 ± 0.11.2 ± 0.1 4.0 ± 0.3 2.5 ± 0.1 k_(q) ¹⁰ (10⁸ M⁻¹ s⁻¹) 2.8 ± 0.1 — — —k_(q) ^(O2) (10⁸ M⁻¹ s⁻¹) 1.6 ± 0.5 — — —

The rate constants for quenching of the triplet excited states ofisatins 3a, 3c, 3e, and 3f by o-xylene 10, triethanol amine 11 andmolecular oxygen were ascertained using laser flash photolysis (FIGS.21-23 ). The quenching of the triplet 3a by molecular oxygen was1.6±0.5×10⁹ M⁻¹s⁻¹ (Table 4; entry 3). Under type II conditions, thecritical step in generating radicals that can initiate free radicalpolymerization is the reaction of triplet states of the photoinitiatorwith the co-initiator (e.g., tertiary amine) The bimolecular quenchingrate constants of triplet state quenching of 3a, 3c, 3e, and 3f by thetriethanol amine 11 were determined by laser flash photolysis.Pseudo-first order treatment for the triplet decay traces of thephotoinitiators 3a, 3c, 3e, and 3f at varying concentrations of 11 wasemployed to extract the bimolecular quenching rate constants 10 from theslope of the inverse triplet lifetimes vs. the concentrations of 11(FIG. 21 ). The quenching high-rate constants (1.2-4.0×10⁸ M⁻¹⁴s⁻¹)ensure efficient initiator radical generation. The similar rateconstants (k_(q) ¹¹) correlate with similar conversions of MMA intopolymer (Table 1). The highest rate constant was observed for 3e (k_(q)¹¹=4.0±0.3×10⁸ M⁻¹s⁻¹) which also showed the highest conversion of 9%(Table 1; entry 10).

Given the success in utilizing a highly colored species for visiblelight photopolymerization without the final polymer being colored, thestrategy is opened up to being utilized for making various industrialapplications such as food packaging, dental composites, and automobiles,where type II aromatic photoinitiators play a major role.

These examples establish the use of isatin and isatin derivatives asvisible light photoinitiators. The onset of absorptivity of isatins ishighly tuneable for visible light initiated photopolymerization. Thepolymerized materials are colorless, indicating that the photoinitiatorscolor is not transferred to the system. This was demonstrated bygenerating transparent films from biomass-derived monomers.

General Methods

All commercially obtained reagents/solvents were used as received;chemicals were purchased from Alfa Aesar®, Sigma-Aldrich®, AcrosOrganics®, TCI America®, and Oakwood® Products, and were used asreceived without further purification. Spectrophotometric grade solvents(e.g. acetonitrile, ethanol) were purchased from Sigma-Aldrich® and usedwithout further purification for emission measurements. Unless statedotherwise, reactions were conducted in oven-dried glassware undernitrogen atmosphere. ¹H-NMR and ¹³C-NMR spectra were recorded on Bruker500 MHz (125 MHz for ¹³C) spectrometers. Data from the ¹H-NMRspectroscopy are reported as chemical shift (6 ppm) with thecorresponding integration values. Coupling constants (J) are reported inhertz (Hz). Standard abbreviations indicating multiplicity were used asfollows: s (singlet), b (broad), d (doublet), t (triplet), q (quartet),m (multiplet), and virt (virtual). Data for ¹³C NMR spectra are reportedin terms of chemical shift (6 ppm).

When necessary, the compounds were purified by combiflash equipped withdual wavelength UV-Vis absorbance detector (Teledyne ISCO) usinghexanes:ethyl acetate as the mobile phase and Redisep® cartridge filledwith silica (Teledyne ISCO) as stationary phase. In some cases,compounds were purified by column chromatography on silica gel (SorbentTechnologies, silica gel standard grade: porosity 60 A, particle size:230×400 mesh, surface area: 500-600 m2/g, bulk density: 0.4 g/mL, pHrange: 6.5-7.5). Unless indicated, the Retention Factor (Rf) values wererecorded using a 5-50% hexanes:ethyl acetate as mobile phase and onSorbent Technologies, silica Gel TLC plates (200 mm thickness w/UV254).

Photophysical Methods

Spectrophotometric solvents (Sigma-Aldrich®) were used whenevernecessary unless or otherwise mentioned. UV quality fluorimeter cells(with range until 190 nm) were purchased from Luzchem®. Absorbancemeasurements were performed using a Cary UV-Vis spectrophotometer.Emission spectra were recorded on a Horiba Scientific® Fluorolog 3spectrometer (FL3-22) equipped with double-grating monochromators, duallamp housing containing a 450-watt CW xenon lamp and a UV xenon flashlamp (FL-1040), Fluorohub/MCA/MCS electronics, and R928 PMT detector.Emission and excitation spectra were corrected in all the cases forsource intensity (lamp and grating) and emission spectral response(detector and grating) by standard instrument correction provided in theinstrument software. Fluorescence (steady state) and phosphorescence (77K) emission spectra were processed by FluorEssence® software.Phosphorescence lifetime measurements were performed using DAS6® V6.4software. The goodness-of-fit was assessed by minimizing the reduced chisquared function and further judged by the symmetrical distribution ofthe residuals. Laser flash photolysis experiments employed the pulsesfrom a Spectra Physics GCR-150-30 Nd:YAG laser (355 nm, ca. 5 mJ/pulse,7 ns pulse length or 266 nm, ca 5 mJ/pulse, 5 ns pulse length) and acomputer-controlled system.

Gel Permeations Chromatography (GPC) Analysis

Polymer sample analysis were performed on EcoSEC GPC System (HLC-8320)equipped with a dual flow refractive index detector (RI) detector.Separation of injections occurred over a column bank consisting of two67.8 mm ID×30 cm, 5 μm particle size TSKgelR multiporeH xL (exclusionlimit 6×104 g/mol) and one 6 mm ID×15 cm, 4 μm particle size TSKgelSuperH-RC (exclusion limit 5×105 g/mol) columns (Tosoh Bioscience LLC).Tetrahydrofuran (THF) (HPLC grade, EMD OmnisolvR) was used as mobilephase and solvent for sample preparation were at flow rate of 1 mL/min.The detector, pump oven, and column oven were maintained at 40° C.Polystyrene kits with PStQuick C (Lot No: PSQ-D02C) and PStQuick C (LotNo: PSQ-C04C) were used. All the molecular weight value (Mw, Mn, andPDI) results are calculated based on a polystyrene calibration curve.

The concentration of polymer samples for GPC analysis was 1 mg/ml inTHF. The samples were soaked overnight. The saturated compounds werefiltered through a 25 mm, 0.2 μm PTFE membrane filter.

Chemical Structures of Isatin Photoinitiators, Co-Initiators, Monomers,and Polymers

Chemical structures of isatins, monomers, and corresponding polymerproducts are shown in FIG. 5 .

General Procedure for the Synthesis of Benzophenone Photoinitiators

Synthesis of N-Methyl Isatin 3c

The synthesis of N-methyl isatin 3c is depicted in FIG. 6 .

N-methyl isatin derivative 3c was synthesized as follows. To a solutionof isatin 3a (2.0 g, 13.6 mmol, 1.0 equiv) in dry DMF (40 mL) under N₂atmosphere at room temperature, K₂CO₃ (3.7 g, 27.2 mmol, 2.0 equiv), andiodomethane (1.0 mL, 19.0 mmol, 1.4 equiv) were added. The resultingmixture was stirred at room temperature over 24 h. After the reaction,red solid precipitate formed was filtered, washed with water, and dried.The pure product 3c was recrystallized from ethanol (without using anychromatographic techniques).

Yield=90%. ¹H NMR (500 MHz, CDCl₃, δ ppm) 7.64-7.58 (m, 1H), 7.14 (td,J=7.6, 0.8 Hz, 1H), 6.91 (d, J=7.9 Hz, 1H), 3.26 (s, 3H). ¹³C NMR (125MHz, CDCl₃, δ ppm) 183.4, 158.2, 151.5, 138.5, 125.3, 123.9, 117.4,110.0, 26.2. FIG. 7A shows the ¹H NMR spectrum of 3c, and FIG. 7B showsthe ¹³C NMR spectrum of 3c.

Synthesis of N-Acetyl Isatin Derivative 3e

The synthesis of N-acetyl derivative 3e is depicted in FIG. 8 .

Isatin 3a (2.0 g, 1 equiv) was dissolved in 20 mL of acetic anhydrideand the reaction mixture was refluxed for ˜5 min. The solution obtainedwas cooled in refrigeration for ˜12 h and the crude solid product 3eformed was separated by vacuum filtration by washing with copious amountof water to remove the acid impurities. The bright reddish green product3e formed was dried and used in the next step without any purification.

Yield=89%. ¹H NMR (500 MHz, CDCl₃, δ ppm) 8.43 (d, J=8.3 Hz, 1H), 7.79(ddd, J=7.6, 1.4, 0.5 Hz, 1H), 7.74 (ddd, J=8.3, 7.6, 1.5 Hz, 1H), 7.36(td, J=7.5, 0.8 Hz, 1H), 2.75 (s, 3H). ¹³C NMR (125 MHz, CDCl₃, δ ppm)180.2, 169.7, 158.0, 148.6, 139.0, 126.2, 125.3, 119.2, 118.3, 26.5.FIG. 9A shows the ¹H NMR spectrum of 3e, and FIG. 9B shows the ¹³C NMRspectrum of 3e.

Synthesis of N-Benzoyl Isatin 3f

The synthesis of N-benzoyl isatin 3f is depicted in FIG. 10 .

Isatin 3a (2.0 g, 1.0 equiv, 13.5 mmol) was dissolved in 40 mL drypyridine and cooled on an ice bath to 0° C. Benzoyl chloride (3.1 mL,2.0 equiv, 27 mmol) was added dropwise to the stirred solution andstirred for ˜2 h. The 2 h reaction mixture was poured onto crushed iceand a yellow colored compound was crashed out. The solid product 3f wasfiltered and dried under reduced pressure to yield pure N-benzoyl isatinderivative 3f.

Yield=90%. ¹H NMR (500 MHz, CD₂Cl₂, δ ppm) 7.99 (dt, J=8.2, 0.7 Hz, 1H),7.82-7.74 (m, 4H), 7.69-7.64 (m, 1H), 7.54-7.49 (m, 2H), 7.37 (td,J=7.6, 0.8 Hz, 1H). ¹³C NMR (125 MHz, CD₂Cl₂, δ ppm) 180.5, 168.0,157.0, 148.9, 138.8, 133.6 133.2, 129.7, 128.4, 126.0, 125.2, 119.3,117.0. FIG. 11A shows the ¹H NMR spectrum of 3f, and FIG. 11B shows the¹³C NMR spectrum of 3f.

Synthesis of 2,5-Bis(Hydroxymethyl) Furan 15

FIG. 12 shows the synthesis of 2,5-bis(hydroxymethyl) furan 15.

5-Hydroxymethylfurfural 14 (5.0 g, 1.0 equiv, 39.6 mmol,) was dissolvedin 5 mL of absolute ethanol and the solution was cooled to 0° C. for ˜10min. Sodium borohydride (0.46 g, 12 mmol, 30 mol %) was added slowly tothe cooled solution and allowed to stir on an ice bath for an hour.After 1 hour, the resultant mixture was warmed to room temperature andstirred for 12 h. Afterwards, —5 g of silica gel was added to thereaction, and ethanol was removed under reduced pressure. The obtainedsolid slurry was used in flash chromatography withdichloromethane/methanol as mobile phase. 2,5-Dialkylsubstituted furanring was detected by a 225 nm detection mode in the instrument. Ayellowish viscous liquid was obtained after the removal of solvent and awhite powder material was formed upon addition of diethyl ether.

R_(f)=0.36 (95% Dichloromethane: 5% Methanol), Yield=82%. ¹H NMR (500MHz, CDCl₃, δ ppm) 6.26 (s, 1H), 4.61 (s, 2H), 1.96 (s, 1H). ¹³C NMR(125 MHz, CDCl₃, δ ppm) 154.0, 108.6, 57.5. FIG. 13A shows the ¹H NMRspectrum of 15, and FIG. 13B shows the ¹³C NMR spectrum of 15.

Synthesis of Furfuryl Dimethacrylate Monomer 6

FIG. 14 depicts the synthesis of furfuryl dimethacrylate monomer 6.

2,5-Bis(hydroxymethyl) furan 15 (4.0 g, 1.0 equiv, 40 mmol) wasdissolved in 100 mL dry dichloromethane and cooled to 0° C.Triethylamine (8.5 mL, 60 mmol) was added dropwise to the cooledsolution and stirred for ˜1 h. Methacryloyl chloride (5.9 mL, 60 mmol)was added dropwise to the reaction mixture and was slowly warmed to roomtemperature and continued stirring for 12 h. Byproduct amine salts wereremoved by vacuum filtration and the filtrate was washed 3×20 mL ofwater and 2×10 mL of NaCl solution. The combined organic layer was driedover anhydrous Na₂SO₄ and solvent was removed under reduced pressure toget the crude product. The crude product was purified by columnchromatography with Hex:EA (10:1) to give oily product 6.

R_(f)=0.4 (85% hexanes: 15% ethyl acetate), Yield=60%. ¹H NMR (500 MHz,CDCl₃, δ ppm) 6.40 (s, 1H), 6.14 (dq, J=1.9, 0.9 Hz, 1H), 5.59 (p, J=1.6Hz, 1H), 5.12 (s, 2H), 1.95 (dd, J=1.6, 1.0 Hz, 3H). ¹³C NMR (126 MHz,CDCl₃, δ ppm) 166.9, 150.2, 135.9, 126.1, 111.5, 58.3, 18.3. FIG. 15Ashows the ¹H NMR spectrum of 6, and FIG. 15B shows the ¹³C NMR spectrumof 6.

Photophysical Studies

FIG. 16 shows UV-Vis absorption spectra of isatin photoinitiators 3a-3fat a concentration of 150 μM in MeCN.

Photopolymerization of Methylmethacrylate Using Isatin Derivatives UnderVisible Light Irradiation

FIG. 17 shows the photopolymerization of methylmethacrylate 4 withisatin photoinitiators.

Methylmethacrylate monomer 4 was freshly distilled and stored underinert atmosphere before the reaction was employed. Photopolymerizationof 4 was performed with isatin photoinitiators 3a-3f with co-initiators10-13 in MeCN/toluene. A solution of photoinitiator 3, co-initiator11-13 (equimolar with photoinitiator) in CH₃CN, or 10 as solvent wasemployed for photopolymerization. The total volume of the polymerizationreaction was =3 mL (1 mL of Monomer, 1 mL of photoinitiator, and 1 mL ofco-initiator). The reaction mixture was prepared in septum sealed pyrextest tube and degassed with N₂ for 15 min to remove dissolved oxygen.Blue LED strip illumination was employed for the reaction with a fluxdensity of 1.27 mW/cm2 (LED jar) and Ee=Flux density (mW/cm2) measuredby Thor PM100D power meter console using S121C photodiode power sensorby keeping the sample at a distance of ˜3 cm from the light source.After the photoreaction, the samples were quenched with 30 mL of coldmethanol, the turbid polymers were filtered by employing buchner funnelvacuum filtration, and the polymers were dried in vacuum over at ˜35° C.for ˜24 h.

Photopolymerization of dimethyl methacrylate 6 and 8 with 3e

FIG. 4 depicts the photopolymerization of dimethyl methacrylate 6 and 8with isatin photoinitiators.

In a silicon mold, a 50-50% blend of monomer 6 or 8 and 3e in o-xylenewas placed and the samples were irradiated by blue LED for 3 h. Afterthe photoreaction, the solvent was removed by placing the cross-linkedpolymer product in vacuum dry oven.

Gel Permeation Chromatography (GPC) Analysis for Acrylate Polymers

Table 1 above displays the GPC analysis for 4 with variousphotoinitiators 3a-3f of methylmethacrylate 4.

FIGS. 18A-18B show GPC traces for 5, when 10 was used assolvent/co-initiator (FIG. 18A), and when 11 was used as co-initiator inMeCN (FIG. 18B) and blue LED irradiation.

Table 3 above shows the GPC analysis of isatin photoinitiators foracrylate polymerization using purple LED.

FIG. 19 shows GPC traces for 5 when 11 is used as co-initiator in MeCNand purple LED irradiation.

Certain embodiments of the compositions and methods disclosed herein aredefined in the above examples. It should be understood that theseexamples, while indicating particular embodiments of the invention, aregiven by way of illustration only. From the above discussion and theseexamples, one skilled in the art can ascertain the essentialcharacteristics of this disclosure, and without departing from thespirit and scope thereof, can make various changes and modifications toadapt the compositions and methods described herein to various usagesand conditions. Various changes may be made and equivalents may besubstituted for elements thereof without departing from the essentialscope of the disclosure. In addition, many modifications may be made toadapt a particular situation or material to the teachings of thedisclosure without departing from the essential scope thereof.

1-2. (canceled)
 3. A composition comprising a compound of Formula III,Formula IP-1, Formula IP-2, Formula IP-3, or Formula IP-10:

wherein: X is O, S, NH, Ge, NC(O)—O—R^(C), N—O—C(O)R^(C), or NO—R^(C),wherein each R^(C) is independently alkyl, aryl, or heteroaryl; and eachof R¹, R², R³, R⁴, and Y is, independently, alkyl, alkene, alkynes,aryl, heterocyclic, alkenyl halide, unsaturated enone, unsaturatedketone, unsaturated amide, unsaturated alcohol, unsaturated amine,unsaturated thiol, phosphonate, carboxylate, sulfonate, nitrile,thioether, thioamide, thioketone, azide, sulfide, disulfide, ether,epoxide, nitrate, nitrite, a nitro compound, a nitroso compound, analkyl ketoesters, an acylgermane, a metallocene, an organosilane, anoxime, an imide, a cyanate, an isocyanate, a thiocyanate, anisothiocyanate, a sulfoxide, a sulfone, a sulfite, a phosphite, a thial,a phosphine, or an aldehyde; the polymer unit is vinyl, stryl, acryl, ora cyclic monomer selected from lactones, epoxides, lactides, lactams,silicon-containing cyclic monomers, and cyclic carbonates; and the amineunit is an amine, thiol, or any hydrogen atom donor; provided, however,that the compound is not isatin.
 4. A composition comprising Formula A:

wherein: dashed lines represent a linker that links X to Y and comprisesan alkyl chain, a carbocycle, a heterocyclic moiety, or a combination ofC—C or C-heteroatom bonds, optionally substituted with one or morehalogens, Y is C═O, C═S, NR¹, P(R²)₂, PR¹R², S, or Se, X is C═O, C═S,NR¹, P(R²)₂, or PR¹R², S, or Se, Z is O, S, or Se, each R¹ is,independently, H, alkyl, aryl, aryloxy, alkoxy, or halo-substitutedalkoxy, and each R² is, independently, H, O, alkyl, aryl, aryloxy,alkoxy, N-alkyl, halo-substituted alkoxy, or halo-substituted N-alkyl;provided, however, that at least one of X or Y is C═O; and furtherprovided that when the linker is phenyl, neither Y nor X is NH. 5-8.(canceled)
 9. The composition of claim 4, wherein: X is NR¹; and R¹ isselected from the group consisting of alkyl, aryl, methoxy, phenoxy, andfluoro-substituted methoxy.
 10. The composition of claim 4, wherein thecomposition has formula B:


11. (canceled)
 12. The composition of claim 4, wherein the linkercomprises an aryl group.
 13. The composition of claim 4, wherein thecomposition comprises N-methyl isatin 3e, N-aryl isatin 3d, N-acetylisatin 3e, N-benzoyl isatin 3f, or N-trifluoromethyl isatin 3g:

14-18. (canceled)
 19. The composition of claim 3, wherein the compoundis compound IP-1a, compound IP-1c, compound IP-1d, compound IP-1e, orFormula IP-1b:

wherein R^(M) is alkyl, aryl, heteroaryl, alkoxy, carboxy alkyl, or anamide. 20-23. (canceled)
 24. The composition of claim 19, wherein thecompound is compound IP-1f, compound IP-1g, or compound IP-1h:

wherein n is an integer;

wherein n is an integer; or

wherein n is an integer; or

wherein n is an integer. 25-28. (canceled)
 29. The composition of claim3, wherein the compound is compound IP-2a, compound IP-2b, compoundIP-2c, compound IP-2d, compound IP-2e, compound IP-2f, compound IP-2g,compound IP-3a, or compound IP-3b:

wherein m and n are each integers; or

wherein m and n are each integers;

30-38. (canceled)
 39. A The composition of claim 3, comprising acompound of Formula IP-4, Formula IP-5, Formula IP-6, Formula IP-7,Formula IP-8, or Formula IP-9:


40. The composition of claim 39, wherein the compound is compound IP-4a,compound IP-4b, compound IP-5a, compound IP-5b, compound IP-5c, orcompound IP-6a:

41-61. (canceled)
 62. The composition of claim 3, wherein the compoundis compound IP-10a or compound IP-10b:


63. (canceled)
 64. A method for making a polymer, the method comprisingexposing a photoinitiator and a monomer to light to produce a polymer,wherein the photoinitiator is isatin or an isatin derivative. 65-75.(canceled)
 76. The method of claim 64, wherein the photoinitiator hasFormula B:

wherein R¹ is H, alkyl, aryl, aryloxy, alkoxy, or halo-substitutedalkoxy.
 77. The method of claim 64, wherein the polymer is colorless ortransparent.
 78. The method of claim 64, wherein the photoinitiatorcomprises isatin 3a, isatin 3d, isatin 3e, isatin 3f, or isatin 3g:

79-83. (canceled)
 84. The method of claim 64, wherein the photoinitiatoris prepared from biomass.
 85. The method of claim 64, wherein the lightis visible light. 86-88. (canceled)
 89. The method of claim 64, whereinthe monomer is methylmethacrylate 4, furfuryl dimethacrylate monomer 6,or dimethylmethacrylate monomer 8:


90. The method of claim 89, wherein the polymer is polymer 5:

wherein n is an integer. 91-93. (canceled)
 94. The method of claim 64,wherein the photoinitiator is compound IP-1a, compound IP-1c, compoundIP-1d, compound IP-1e, compound IP-1f, compound IP-1g, compound IP-1h,compound IP-2a, compound IP-2b, compound IP-2c, compound IP-2d, compoundIP-2e, compound IP-2f, compound IP-2g, compound IP-3a, compound IP-3b,compound IP-4a, compound IP-4b, compound IP-5a, compound IP-5b, compoundIP-5c, compound IP-6a, compound IP-6b, compound IP-7a, compound IP-7b,compound IP-7c, compound IP-7d, compound IP-7e, compound IP-8a, compoundIP-8a, compound IP-9a, compound IP-9b, compound IP-10a, or compoundIP-10b:

wherein n is an integer;

wherein n is an integer;

wherein n is an integer; or

wherein n is an integer;

wherein m and n are each integers; or

wherein m and n are each integers;

wherein R^(M) is alkyl, aryl, heteroaryl, alkoxy, carboxy alkyl, or anamide;

wherein n is an integer;

95-97. (canceled)
 98. The method of claim 64, wherein the photoinitiatoris a compound of Formula IP-1b:

wherein R^(M) is alkyl, aryl, heteroaryl, alkoxy, carboxy alkyl, or anamide. 99-138. (canceled)
 139. The method of claim 64, wherein aco-initiator is exposed to the light with the photoinitiator and themonomer. 140-148. (canceled)